Resistive switching in multiferroic BiFeO3 films: Ferroelectricity versus vacancy migration
Abstract
We studied the voltage-induced resistive switching (RS) in ferroelectric/metal (BiFeO3/Nb:SrTiO3) vertical devices. We found switching with RON and ROFF ratios of ΔR = 1-RON/ROFF = 0.82 at voltages starting at VSET, RESET = ±2 V. Upon increasing voltage, ΔR also increases until dielectric breakdown is reached. Interestingly, the VSET, RESET values at which the RS becomes significant, coincides with the coercive voltage of the ferroelectric polarization, as measured by piezoelectric force microscopy in similar BiFeO3 films. This suggests that the driving mechanism of the RS effect in our films is connected to the BiFeO3 ferroelectricity. However, the increase of the RS effect after complete ferroelectric saturation points to an additional mechanism that may be related to vacancy displacements. This is further supported by forming process necessary to induce resistance bi-stability, typical of an RS effect.
- Publication:
-
Solid State Communications
- Pub Date:
- February 2019
- DOI:
- 10.1016/j.ssc.2018.11.005
- Bibcode:
- 2019SSCom.288...38C
- Keywords:
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- A. Oxide thin films;
- D. Resistive switching;
- D. Memristors